#include<iostream>
using namespace std;
int main(){
  double a[10]={28.9,32.7,45.6,78,35,86.2,27.8,43,56,65};
  double sum=0,num;
  for(double x:a){
    cin>>num;
    sum+=x*num;
  }
  cout.precision(1);
  cout<<fixed;
  cout<<sum;
}